So I just put together a new pc the other day, and it fails to boot up sometimes, and run grand the next.

Usually when I hit the power button, it will power up, spin the fans for a few seconds, then cut out. After doing this a couple of times, sometimes it will boot successfully and will continue running grand until I turn it off. However, if I turn it off after its been running for a while, usually it will be able to power back on straight away.

Now, I've a fairly big heatsink on it, with 120mm fans pulling from and to the front and back panals, and a side 250mm pullling air onto the mobo and processors. Its kinda seems like when the components are too cold somethings not connecting, and when it heats up a bad connection on the mobo it expands or something.

Hopefully will be able to get my hands on a reliable 750w psu over the next few days, not sure about a mobo. Anyone got any ideas to help me out here?